Reflex reflector

ABSTRACT

A reflex reflector for retrodirecting illumination from the lamps of an approaching motor vehicle includes an array of interfitting V-block shaped cube corners having three mutually perpendicular reflecting faces within a frontal rectangular boundary. Each cube corner includes a first face bounded by a short side of the rectangle and the diagonals therefrom, a second face bounded by a long side and the diagonals therefrom including the diagonal common with the first face, and a third face bounded by the opposite short side and the diagonals therefrom including the diagonal common with the second face. In the array, the faces mate with the corresponding faces of juxtaposed adjacent cube corners to form a rectangular reflex strip. The reflector, when positioned vertically, redirects the intercepted illumination upwardly to the driver of the approaching vehicle.

United StatesPatent [191 Montgomery [451 Dec. 3, 1974 i REFLEX REFLECTOR[75] Inventor: James R. Montgomery, Anderson,

Ind.

[73] Assignee: General Motors Corporation,

Detroit, Mich.

[22] Filed: Sept. 24, 1973 [21] Appl. No.: 400,241

[52] US. Cl 350/103, 350/100, 350/109 [51] lnt. Cl. G021) 5/12 [58]Field of Search 350/288, 97, 100, 102,

[56] References Cited UNITED STATES PATENTS 2,055,298 9/1936 Leray...350/103 3,450,459 6/1969 Haggerty 350 103 3,541,606 11/1970 Heenan et al350/103 Primary Examiner-Ronald L. Wibert Assistant Examiner-Michael J.Tokar Attorney, Agent, or FirmPeter D. Sachtjen [5 7] ABSTRACT A reflexreflector for retrodirecting illumination from the lamps of anapproaching motor vehicle includes an array of interfitting V-blockshaped cube corners having three mutually perpendicular reflecting faceswithin a frontal rectangular boundary. Each cube corner includes a firstface bounded by a short side of the rectangle and the diagonalstherefrom, a second face bounded by a long side and the diagonalstherefrom including the diagonal common with the first face, and a thirdface bounded by the opposite short side and the diagonals therefromincluding the diagonal'common with the second face. In the array, thefaces mate with the corresponding faces of juxtaposed adjacent cubecorners to form a rectangular reflex strip. The reflector, whenpositioned vertically, redirects the intercepted illumination upwardlyto the driver of the approaching vehicle.

1 Claim, 10 Drawing Figures PATENTLL EU) 3 I974 sum 28? 2 REFLEXREFLECTOR The present invention relates to reflex reflectors, and inparticular, to a reflex reflector for a motor vehicle having a cubecorner array producable in strip form and having a substantiallyunidirectional response to intercepted illumination.

Reflex reflectors currently used on motor vehicles for reflecting lightfrom an approaching vehicle back to the driver thereof employ an arrayof hexagonal shape reflex cube corners. Each cube corner is in the formof a trihedron three mutually perpendicular reflecting faces. Such acube corner returns the incident light to six sectors about its axis.Thus, the reflex area functions to redirect light to areas not visibleby the approaching driver. However, inasmuch as current motor vehicleregulations only require that the incident light be returned upwardly tothe driver, the portions of the reflex cube corners contributing to thenon-visible reduction are superfluous and not necessary for satisfyingthe lighting standards.

The present invention provides a reflex reflector having minimal cubecorner area for redirecting light within the desired upward viewingsector. The areas providing sideward response are eliminated and thecube area is confined to those portions essential for providing upwardresponse. More particularly, the rear surface at the reflector iscomprised of a plurality of interfitting V-block shaped cube corners.Each cube corner is located within a'V-grooved rectangular boundary. Thecube corner has a side face bounded by the long side of rectangle andthe diagonals therefrom intersecting at the cube corner central axis,and upper and lower faces symmetrically disposed with respect to theside face and bounded by the short sides of the rectangle and thediagonals extending therefrom and intersecting at the axis. In the cubecorner array, the faces mate with the corresponding faces of adjacentjuxtaposed cube corners. Two adjacent rows form a rectangular strip.

The pins for forming the cube corners are also disclosed. The pins aregenerally rectangular bodies having a longitudinal V-groove formedtherein. The sides of the groove extend outwardly from a centroidal axisalong the diagonals intersecting the opposed short side walls. The pinelements are interfitted in an array corresponding to the desired cubecorner cluster to form a rectangular strip. An electroform is made ofthe pin by conventional processes. The resulting electroform strip iscut to form desired reflex area for ultimate use in the reflector moldcavity.

The reflex reflector then functions to return light vertically withrespect to the axis of the cube cornerKThe intercepted light from afollowing vehicle thus impinge upon one of the lower faces andinternally reflected onto the side face and upwardly therefrom to theupper face for redirection to the driver.

These and other features of the present invention will be apparent tothose skilled in the art upon reading the following detaileddescription, reference being made to the accompanying drawingsillustrating a preferred embodiment in which:

FIG. 1 is a side elevational view of two motor vehicles illustrating thelight return path from the headlamps of an approaching motor vehicle asprovided by the reflex reflector made in accordance with the presentinvention mounted on the leading vehicle;

the vertical strips of interfitting cube corners;

FIG. 3 is an enlarged rear view of an isolated cube corner;

FIG. 4 is a view taken along line 4-4 of FIG. 2; FIG. 5 is a view takenalong line 5-5 of FIG. 2;

FIG. 6 is a front view of a reflex pin used in forming the cube cornersof FIG. 2;

FIG. 7 is a side view of the reflex pin taken along line 7-7 of FIG. 6;

FIG. 8 is a side view of the reflex pin taken along line 88 of FIG. 6;

FIG. 9 is an exploded perspective view showing a plurality of reflexpins aligned in spaced relationship; and

FIG. 10 is a perspective view of the pins of FIG. 9 interfitted toestablish the array used in forming the cube corners of FIG. 2.

Referring to FIG. 1, there is shown a leading motor vehicle 10 and anapproaching or trailing motor vehicle 12. Light from the headlamps 14 ofthe trailing motor vehicle 12 horizontally impinge upon a reflexreflector mounted on the rear of the vehicle 10 along ray 18. The lightis upwardly retrodirected from the reflector 16 along ray 20 to thedriver 22 of the motor vehicle 12.

Reflex reflectors as used herein refer to devices which are used onmotor vehicles to give an indication to an approaching driver byreflected light from the lamps on the approaching vehicle. They aregenerally designed to be visible at night within a specified range,particularly when illuminated by the lower beam of the headlamps.

Certain angular relationships are used'in prescribing the performance ofreflex reflectors. The angle 6 (theta) between the driver 22 along ray20 and a horizontal ray 18 between the headlamps 14 and the center ofthe reflex reflector 16 is known as the observation angle. The angle (1)(phi) between the ray l8 and the optical axis 24 of the reflector 16 isdesignated the entrance angle. The current Federal Motor Vehicle SafetyStandards require that, for particular observation angles generally 0.2up and l.5 up, certain minimum candlepower per incident foot-candle ofillumination be reflected at prescribed entrance angles."

In conventional three corner reflector cubes, it is known that a singleincident beam of light is broken into six distinct illumination sectors.The sectors occur at about 0.2 of the center axis of the cube. Forconventional cube orientation the sectors are located above, below, leftand right of the cube axis. Thus, only a portion of the cube cornerfaces are used in the actual return of the requisite up illumination. Areflex reflector made in accordance with the present invention, on theother hand utilizes only those areas of the cube corner reflecting faceswhich are necessary for returning this requisite up" illumination.

More particularly and referring to FIG. 2, the reflex reflector 16comprises a molded plastic body 30 including a pair of rectangularreflex areas 32 molded on its rear surface. Each of the reflex areas 32is comprised of an array of interfitting V-block shaped cube cornerstypically indicated by the numeral 34.

For purposes of description, an isolated cube corner 34a is shown inFIG. 3. The cube corner 34 is located within a generally rectangularboundary and comprises a side face 40, an upper face 42, and a lowerface 44.

The three faces 40, 42 and 44 form a trihedron wherein the faces aremutually perpendicular. The faces have an apex 45 at the cube axis 46.The axis 46 may bear various angular relationships to the normal to thefrom face of the reflector to return incident light in the desired updirection.

' The side face 40 is bounded by a vertical edge 50 and diagonals S2 and54 extending from the ends thereof intersecting at the axis 46. Theupper face 42 is bounded by the upper short edge 56 of the rectangle andthe diagonals 52 and 58 extending from the ends thereof andintersectingat the axis 46. Diagonal 58 is a continuation of diagonal54. The diagonal 52 constitutes an edge common to the faces 40 and 42.The lower face 44 is symmetrically disposed about the side face 40 withrespect to the upper face 42. The lower face 44 is bounded by the lowershort edge 60 and the diagonals S4 and 62 extending from the endsthereof and intersecting the axis 46. The diagonal edge 54 is commonwith the side face 40 and the lower face 44. The periphery of the cubecorner 34 is thus defined by the edges 60, 50, 56 and the \/-shapeddiagonal edges 58 and 62'.

When mounted on a vehicle, light impinging upon reflector 16 from anapproaching vehicle will be refracted at the front surface thereof andimpinge upon face 44. It will be totally internally reflected therefromonto the side face 40 and reflected therefrom to the face 42 for upwardreflection and refraction along ray to the driver 22. The reverserouting along faces 42, 40, 44 also occurs.

Each cube corner thus individually reflects illumination from thetrailing vehicle upwardly within the prescribed observation angle. Therequisite candlepower per incident foot candle of illumination isestablished by providing an array of cube corners having sufficientreflecting area to meet the requirements. This is achieved in' thepresentdesign by interfitting an array of cube corners 34 which havesufficient area to provide the desired reflectivity. For purposes ofillustration, starting at the left-hand edge of FIG. 2, a vertical rowof three cube corners is shown. Each corner includes faces 44, 40 and42. The corresponding faces of juxtaposed adjacent cubes 34 and 34" matewith the corresponding faces of the adjacent cube corners. A cube corneris provided at the upper and lower righthand boundaries. The sequence isrepeated vertically along the area 32. With regard to an adjacent reflexarea, the side faces 40 mate, although this is not necessary inasmuch asthe areas are independent. The faces 40 thus define the vertical edgesof the reflex area 32. When positioned adjacent the similar reflex area,the desired reflex area is formed.

The reflex areas are formed by an electroform mold insert. The inserthas recesses corresponding to the individual cube corners. The insert ismade by conven tionally electro-forming the faces of pins hereinafterdescribed, cutting the electroform to a desired length and inserting itin the mold cavity. The molded article accordingly will have cubecorners conforming to the 'faces to these pins.

The individual pins in front view are identical to the aforementionedcube corners 34. However, each is formed from generally rectangularstock and has a longitudinal V-shaped groove 72 formed coincident withthe diagonals extending from the long side of the rectangular body andintersecting at the apex or centroidal axis 74. The pin has a side face76 corresponding to the side face 40 of the cube corner, an upper face78 corresponding to the upper face 42 of the cube corner, and a lowerface 80 corresponding to the lower face 44 of the cube corner 34. Thethree faces 76, 78 and 80 are mutually perpendicular about the axis 74.The pin element 70 thus has a lower sidewall 90, an upper sidewall 92and a vertical sidewall 93. The groove is formed by intersectingsidewalls 94 and 96. As shown in FIG. 9, the generally V-block shapedbodies are adapted to interfit. The sidewall 94 mates with ajuxtaposedadjacent sidewall 94 of an identical pin element. Correspondingly, thewall 96 mates with an identical wall of an adjacent juxtaposed pinelement, The walls similarly mate with adjacent elements.

As previously mentioned, by a suitable conventional electroform process,a mold insert is established having trihedral recesses in the form ofthe mutually perpendicular faces of the individual pins. When thiselectroform is cut to the desired length and width and inserted in themold cavity, the molded article will thus have the aforementioned cubecorners 34, each of which corresponds to the mutually perpendicularfaces of an individual pin.

Each cube corner will optically perform as above recited whereinillumination from the headlamps 14 impinging upon the lower face 44 willbe internally reflected onto the side face 40 and therefrom onto theupper face 42 for redirection along ray 20 to the driver of the vehicle.By eliminating extraneous left and right response and the reflectingareas therefor, the overall reflex area required for providing thedesired upward response is reduced and reflexing efficiency maximized.

Although only one form of this invention has been shown and described,other forms will be readily apparent to those skilled in the art.Therefore, it is not intended to limit the scope of this invention bythe embodiment selected for the purpose of this disclosure but only bythe claims which follow.

What is claimed is:

1. A reflex reflector comprising: an array of interfitting V-blockshaped cube corners having three mutually perpendicular reflecting faceswithin a frontal re ctangular boundary and intersecting at an apex, eachof said cube corners including a first base bounded by a short side andthe diagonals from the ends thereof to the apex, a second face boundedby a long side and the diagonals from the ends thereof to the apexincluding the diagonal common with the first face, and a third facebounded by the opposite short side and the diagonals from the endsthereof to the apex including the diagonal common with the second face,the individual faces mating in the array with the corresponding faces ofjuxtaposed adjacent cube corners to form a rectangular reflex strip.

1. A reflex reflector comprising: an array of interfitting Vblock shapedcube corners having three mutually perpendicular reflecting faces withina frontal rectangular boundary and intersecting at an apex, each of saidcube corners including a first base bounded by a short side and thediagonals from the ends thereof to the apex, a second face bounded by along side and the diagonals from the ends thereof to the apex includingthe diagonal common with the first face, and a third face bounded by theopposite short side and the diagonals from the ends thereof to the apexincluding the diagonal common with the second face, the individual facesmating in the array with the corresponding faces of juxtaposed adjacentcube corners to form a rectangular reflex strip.